I am trying to create a Python script which calculates the final amount to be paid when given a list of books.

menu = 3
while menu == 3:
    print ("Select book option")
    print ("1 Moby Dick (1851)- £15.20")
    print ("2 The Terrible Privacy of Maxwell Sim (2010) - £13.14")
    print ("3 Still Life With Woodpecker (1980) - £11.05")
    print ("4 Sleeping Murder (1976) - £10.24")
    print ("5 Three Men in a Boat (1889) - £12.87")
    print ("6 The Time Machine (1895) - £10.43")
    print ("7 The Caves of Steel (1954) - £8.12")
    print ("8 Idle Thoughts of an Idle Fellow (1886) - £7.32")
    print ("9 A Christmas Carol (1843) - £4.23")
    print ("10 A Tale of Two Cities (1859) - £6.32")
    print ("11 Great Expectations (1861) - £13.21")
    
def option():
    while True:
        option = int(input('select an option from 1 to 11 '))
        if option > 11 or option < 1:
            print ("Option not avialable. Try again! ")
            option()
        elif option == 1:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter Y to add another option or N to finish: ')
            if cont == "N":
                   exit
            elif cont == "Y":
                   menu = 3
                   
            else:
                   break
        elif option == 2:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter Y to add another option or N to finish: ')
            def dis10(option, dis):
                option = 13.14
                dis = option * 0.1
                dis10 = option - dis
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        elif option == 3:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        elif option == 4:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        elif option == 5:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        elif option == 6:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        elif option == 7:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        elif option == 8:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        if option == 9:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        elif option == 10:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
        elif option == 11:
            print ("You select option 1 Moby Dick (1851)- £15.20")
            cont = input('Enter "Y" to add another option or "N" to finish: ')
            if cont == "N":
               exit
            elif cont == "Y":
               menu = 3
            else:
                   break
def totaldis(total_amount, totaldis):
    totaldis = total_amount -